stwETCH is a playable granular time-stretching / buffer repeater effect capable of stretching up to 500% normal length using granule sizes ranging from 10 to 500 ms, meaning that relatively smooth and total whack-job are both possibilities here. Further to this there are 2 pitch controls: one that controls granule playback speed, aka speed control (like tape), and one that controls pitch-shift, aka pitch (like a pitchshifter).
stwETCH was designed as a control surface playable instrument - in a similar vain to wavePLAY. It is entirely monophonic and whilst it has MIDI support, it won't respond to any plain old note-on data. stwETCH wants nothing but CCs - even the play switch. So, play it from a control surface (or VST automation parameters) or use MIDI CC - just don't expect it to respond to you playing the notes on a keyboard.
A mono version of stwETCH is available for free (the full version is stereo).